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<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy"></a><a class="link" href="is_valid_3_with_failure_value_and_strategy.html" title="is_valid (with failure value and strategy)">is_valid
          (with failure value and strategy)</a>
</h5></div></div></div>
<p>
            <a class="indexterm" name="idm45246436317024"></a>
Checks if a geometry is valid (in the OGC sense)
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h0"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.synopsis"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.synopsis">Synopsis</a>
          </h6>
<p>
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Strategy</span><span class="special">&gt;</span>
<span class="keyword">bool</span> <span class="identifier">is_valid</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="identifier">validity_failure_type</span> <span class="special">&amp;</span> <span class="identifier">failure</span><span class="special">,</span> <span class="identifier">Strategy</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">strategy</span><span class="special">)</span></pre>
<p>
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h1"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.parameters"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.parameters">Parameters</a>
          </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                    <p>
                      Type
                    </p>
                  </th>
<th>
                    <p>
                      Concept
                    </p>
                  </th>
<th>
                    <p>
                      Name
                    </p>
                  </th>
<th>
                    <p>
                      Description
                    </p>
                  </th>
</tr></thead>
<tbody>
<tr>
<td>
                    <p>
                      Geometry const &amp;
                    </p>
                  </td>
<td>
                    <p>
                      Any type fulfilling a Geometry Concept
                    </p>
                  </td>
<td>
                    <p>
                      geometry
                    </p>
                  </td>
<td>
                    <p>
                      A model of the specified concept
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      validity_failure_type &amp;
                    </p>
                  </td>
<td>
                  </td>
<td>
                    <p>
                      failure
                    </p>
                  </td>
<td>
                    <p>
                      An enumeration value indicating that the geometry is valid
                      or not, and if not valid indicating the reason why
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Strategy const &amp;
                    </p>
                  </td>
<td>
                    <p>
                      Any type fulfilling a Is_valid Strategy Concept
                    </p>
                  </td>
<td>
                    <p>
                      strategy
                    </p>
                  </td>
<td>
                    <p>
                      The strategy which will be used for is_valid calculations
                    </p>
                  </td>
</tr>
</tbody>
</table></div>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h2"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.returns"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.returns">Returns</a>
          </h6>
<p>
            Returns true if the geometry is valid (in the OGC sense); furthermore,
            the following geometries are considered valid: multi-geometries with
            no elements, linear geometries containing spikes, areal geometries with
            duplicate (consecutive) points
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h3"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.header"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.header">Header</a>
          </h6>
<p>
            Either
          </p>
<p>
            <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
          </p>
<p>
            Or
          </p>
<p>
            <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">algorithms</span><span class="special">/</span><span class="identifier">is_valid</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h4"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.conformance"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.conformance">Conformance</a>
          </h6>
<p>
            The function is_valid is not defined by OGC.
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h5"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.supported_geometries"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.supported_geometries">Supported
            geometries</a>
          </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                    <p>
                      Geometry
                    </p>
                  </th>
<th>
                    <p>
                      Status
                    </p>
                  </th>
</tr></thead>
<tbody>
<tr>
<td>
                    <p>
                      Point
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Segment
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Box
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Linestring
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Ring
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Polygon
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      MultiPoint
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      MultiLinestring
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      MultiPolygon
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
<tr>
<td>
                    <p>
                      Variant
                    </p>
                  </td>
<td>
                    <p>
                      <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
                    </p>
                  </td>
</tr>
</tbody>
</table></div>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h6"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.complexity"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.complexity">Complexity</a>
          </h6>
<p>
            Constant-time for points, segments, boxes and multi-points
          </p>
<p>
            Linear for linestrings and multi-linestrings
          </p>
<p>
            Linearithmic for rings
          </p>
<p>
            Currently, worst-case quadratic for polygons and multi-polygons
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h7"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.example"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.example">Example</a>
          </h6>
<p>
            Checks whether a geometry is valid and, if not valid, checks if it could
            be fixed by bg::correct; if so bg::correct is called on the geometry
          </p>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>

<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">point_xy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>


<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
<span class="special">{</span>
    <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">d2</span><span class="special">::</span><span class="identifier">point_xy</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span> <span class="identifier">point_type</span><span class="special">;</span>
    <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">polygon</span><span class="special">&lt;</span><span class="identifier">point_type</span><span class="special">&gt;</span> <span class="identifier">polygon_type</span><span class="special">;</span>

    <span class="identifier">polygon_type</span> <span class="identifier">poly</span><span class="special">;</span>
    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">read_wkt</span><span class="special">(</span><span class="string">"POLYGON((0 0,0 10,10 10,10 0),(0 0,9 2,9 1,0 0),(0 0,2 9,1 9,0 0))"</span><span class="special">,</span> <span class="identifier">poly</span><span class="special">);</span>

    <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"original geometry: "</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">dsv</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">validity_failure_type</span> <span class="identifier">failure</span><span class="special">;</span>
    <span class="keyword">bool</span> <span class="identifier">valid</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">is_valid</span><span class="special">(</span><span class="identifier">poly</span><span class="special">,</span> <span class="identifier">failure</span><span class="special">);</span>

    <span class="comment">// if the invalidity is only due to lack of closing points and/or wrongly oriented rings, then bg::correct can fix it</span>
    <span class="keyword">bool</span> <span class="identifier">could_be_fixed</span> <span class="special">=</span> <span class="special">(</span><span class="identifier">failure</span> <span class="special">==</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">failure_not_closed</span>
                           <span class="special">||</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">failure_wrong_orientation</span><span class="special">);</span>
    <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"is valid? "</span> <span class="special">&lt;&lt;</span> <span class="special">(</span><span class="identifier">valid</span> <span class="special">?</span> <span class="string">"yes"</span> <span class="special">:</span> <span class="string">"no"</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
    <span class="keyword">if</span> <span class="special">(!</span> <span class="identifier">valid</span><span class="special">)</span>
    <span class="special">{</span>
        <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"can boost::geometry::correct remedy invalidity? "</span> <span class="special">&lt;&lt;</span> <span class="special">(</span><span class="identifier">could_be_fixed</span> <span class="special">?</span> <span class="string">"possibly yes"</span> <span class="special">:</span> <span class="string">"no"</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
        <span class="keyword">if</span> <span class="special">(</span><span class="identifier">could_be_fixed</span><span class="special">)</span>
        <span class="special">{</span>
            <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">correct</span><span class="special">(</span><span class="identifier">poly</span><span class="special">);</span>
            <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"after correction: "</span> <span class="special">&lt;&lt;</span> <span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">is_valid</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">?</span> <span class="string">"valid"</span> <span class="special">:</span> <span class="string">"still invalid"</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
            <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"corrected geometry: "</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">dsv</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
        <span class="special">}</span>
    <span class="special">}</span>

    <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
          </p>
<p>
            Output:
          </p>
<pre class="programlisting">original geometry: (((0, 0), (0, 10), (10, 10), (10, 0)), ((0, 0), (9, 2), (9, 1), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))
is valid? no
can boost::geometry::correct remedy invalidity? possibly yes
after correction: valid
corrected geometry: (((0, 0), (0, 10), (10, 10), (10, 0), (0, 0)), ((0, 0), (9, 1), (9, 2), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))

<img src="../../../../img/algorithms/is_valid_failure_example.png" alt="is_valid_failure_example">

</pre>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h8"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.see_also"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.see_also">See
            also</a>
          </h6>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
                <a class="link" href="../is_simple.html" title="is_simple">is_simple</a>
              </li>
<li class="listitem">
                <a class="link" href="../../enumerations/validity_failure_type.html" title="validity_failure_type">validity_failure_type</a>
              </li>
</ul></div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="right"><div class="copyright-footer">Copyright © 2009-2021 Barend Gehrels,
      Bruno Lalande, Mateusz Loskot, Adam Wulkiewicz, Oracle and/or its affiliates<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
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